Optical MEM (micro-electro-mechanical) devices have applications in display, print, optical and electrical technologies. An optical MEM device, herein, is a device that is capable of constructively and destructively interfering with an incident light source to produce an optical signal or optical signals. Exemplary optical MEM devices, and methods for making the same, are disclosed in U.S. Pat. Nos. 5,311,360, 5,841,579 and 5,808,797, issued to Bloom et al., the contents of which are hereby incorporated by reference.
Optical MEM devices can be fabricated from Si-based materials using lithographic techniques. Optical MEM devices can have reflective ribbons that are formed over a suitable substrate structure such that the ribbons are spatially arranged in parallel and are coupled to the substrate structure. In use, a portion of the reflective ribbons can be moved by applying an operating bias voltage, or switching voltage, across the ribbons and the substrate structure. By alternating, or switching, the potential of the bias voltage, the ribbons are alternated between the positions for constructive and destructive interference with the incident light source to generate optical signals.
Variations in the optical signals can occur for a variety of reasons including polarization of the light, interactions of the light with the ribbon edges, light loss through spaces between the ribbons and aging effects. Variability in the optical signals can be catastrophic in applications where consistent or reproducible optical signals are required, such as in the case of optic communications. Therefore, there is a need for an optical MEM device that is capable of producing stable or reproducible optical signals during operation.